#include"my_stdio.h"
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
mFILE *mfopen(const char *filename,const char *mode)
{
   int fd = -1;
   if(strcmp(mode,"r") == 0)
   {
      fd = open(filename, O_RDONLY); 
   }
   else if(strcmp(mode,"w") == 0)
   {
      fd = open(filename,O_CREAT|O_TRUNC|O_TRUNC,0666);
   }
   else if(strcmp(mode,"a") == 0)
   {
      fd = open(filename,O_CREAT|O_WRONLY|O_APPEND,0666);
   }

   if(fd < 0) return NULL;

   mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
   if(!mf) 
   {
      close(fd);
      return NULL;
   }

   mf->fileno = fd;
   mf->flag = FLUSH_LINE;
   mf->cap = SIZE; 
   mf->size = 0;
   return mf;
}


void mfflush(mFILE *stream)
{
   if(stream->size > 0)
   {
      write(stream->fileno,stream->outbuffer,stream->size);
      //刷新到外设
      stream->size = 0;
   }
}

int mfwrite(const void *ptr, int num, mFILE *stream)
{
   // 1.拷贝
   memcpy(stream->outbuffer+stream->size,ptr,num);
   stream->size += num;

   // 2.检测是否要刷新
   if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1] == '\n')
   {
      mfflush(stream);
   }
   return num;
}


void mfclose(mFILE *stream)
{
   if(stream->size > 0)
   {
      mfflush(stream);
   }
   close(stream->fileno);
}



